It is desirable to make the cylinder slots or grooves as narrow as possible so that, with a given cylinder diameter, as much space around the circumference can be used for printing as possible, and as little space as possible when the blanket is inserted for tensioning about the cylinder. The ends of a blanket, or similar cover, which is generally flexible, can be fitted into the groove usually only by use of tools. Typical tools which are used to assist in the insertion of blankets in the grooves are screwdrivers, painter's knives and scrapers, and other tools which are, generally, elongated and essentially flat, while being strong. In order to permit insertion of the ends of a covering blanket, the grooves have been made wide enough to permit insertion of one end portion, and then not only insertion of the second end portion but, additionally, provide space for a tool or pusher element which is used to assist in stretching a rubber blanket about the cylinder.